Subject: AC Compress Clutch Control Unit: Was 89 100 AC Control Head (Climate
Control) Diagnostic
89 100 (manufactured after 1988)
Climate Control Diagnosis, the saga continues.
The direct question:
Where in the heck is the A/C Compressor Clutch Control Unit?
The story:
Thanks to everyone who helped me find a replacement AC Control Head. I picked
up one for $42.00 at my favorite junk yard back home in PA. Unfortunately I
didn't need one. The diagnostic path in the Bentley manual clearly shows that
when the unit is OK a single point of light will appear on the display during
the testing of track 17. Unfortunately the related figure also shows all of the
other light segments (just for my information). I was under the impression that
all light segments needed to be working to pass the test. I saw the light (pun
intended) over the weekend and continued on with the diagnosis. I eventually
came to a place that asks me to analyze the circuit from the A/C Programmer pin
5. I can't find the other end of the wire to test the circuit. Here's what I
"think" I know so far.
-Pin 5 on A/C Programmer attaches to Black Wire with Red Stripe and
goes to the A/C Thermostat Switch.
- AC Thermostat switch is normally closed unless the A/C is in danger of
freezing.
It's not working at the moment so I assume the circuit should be working
(closed).
- Wire color changes to Black
- Then on down the line of cable track 397
- Through connector T6/2 color changes to Brown.
- Direct link to Cable Track 395
- 395 becomes a much larger Green wire
- T8c/4 becomes Green with yellow stripe
- Goes straight into the A/C Compressor Clutch.
- A Green wire leaves the A/C Compressor Clutch to Cable Track 415
- and finally goes into the A/C Compressor Clutch Control Unit. 8/87
At the moment pin 5 from the top of this list has no voltage and I don't think
it's grounded either. So, I must find where the power comes from.
Finally a question:
Where in the heck is the A/C Compressor Clutch Control Unit?
Thanks for taking the time to read this long post. If you have any
other helpful guidance I'd be grateful to hear it.
Regards,
DPowell